Ventilators are common air circulating devices for exhausting the indoor air. FIG. 1 is a schematic view of a ventilator 100. As shown in FIG. 1, cover 10 covers a machine body 11. FIG. 1 shows the front side of the cover 10. FIG. 2 is a schematic view of the mounting side of the cover 10 where the cover 10 is mounted onto the body 11. A screw 12 is screwed into the iron block 14 for securing a spring 13 with the cover 10. The screw 12 is drilled directly into the cover 10.
When the cover 10 is made of a PBT material, residual stress may be generated during the shaping of the cover 10 due to the characteristic of the PBT. In that case, if the screw 12 having permeable chemical substance stuck thereon is directly screwed into the cover 10, cracks or breakage may occur in the cover 10 made of PBT material and therefore the cover 10 may not be stably mounted and there is a risk that the cover might drop from the body 11.
Therefore, it is desirable to provide a stable and reliable fixing structure for mounting the spring of the ventilator cover.